Piezo elements are used, inter alia, for positioning elements, ultrasonic transducers, sensors and in inkjet printers. The function of a piezo element is based on the deformation of piezoceramic materials such as, for example, lead-zirconate-titanate, under the effect of an electrical field. If an electrical voltage is applied to the piezo element, said element expands in the perpendicular direction with respect to the electrical field which is generated by the electrical voltage.
The advantages of piezo elements are, inter alia, their relatively high speed, their relatively high degree of effectiveness and their relatively short actuation path when they are used as a piezo actuator.
However, if a relatively large actuation path is to be brought about with the piezo actuator, a piezo stack composed of a plurality of alternately successive piezoelectric layers and internal electrode layers is used for the piezo actuator.
In order to prevent the expansion of the piezo stack causing the possible occurrence of damaging fractures in the piezo stack in the transverse direction with respect to the internal electrode layers, mechanical stress within the piezo stack which is due to the expansion should remain below a level which is non-damaging for the piezoceramic material. This can be achieved, for example, by dividing the piezo stack into relatively short sections.